Study On The Emulsification And Application Of Pickering Emulsions Based On Functional Particles

Emulsion stabilized by solid particles is termed as Pickering emulsion, and has been widely used in many fields. Functional particles as stabilizer would impart Pickering emulsions with its functional feactures, and has attracted many attentions for its high potential values. Nowadays, the preparation and application of Pickering-type sizing emulsion has been studied a lot, however, the introduction of functional Pickering emulsion into paper-sizing emulsion and wastewater treatment system is rarely blank. For developing novel sizing emulsion and wastewater treatment system, this paper was mainly conducted on the stability, stabilization mechanism, stimulative-responsibility and sizing feactures of sizing emulsion. This study also explored a new system for extracting phenolic compounds from effluent by magnetic Pickering emulsion liquid membrane, and systemically analyzed the extracting process and influencing factors. This research will contribute to the development of new paper sizing agent and separation system, provide theoretical foundation and technical support. 1. Pickering-type ODSA emulsions stabilized with magnetic Fe3O4 nanoparticles. The surface charge and adsorption behavior on oil/water interface of particles would be affected by pH value. When pH>7.2, the setting stability of Pickering emulsion was gradually improved The emulsion has the best stability at the volume ratio of 1:lwith ODSA/dodecane. Increasing particles concentration would make for encapsulation efficiency of particulate film and hydrolysis stability of ODSA. When particles concentration excessed the critical value of 1.0 wt%, nanoparticles would be serious aggregated, then destroyed the stability of Pickering emulsion. The images of SEM and CLSM indicated that particles adsorbed onto oil/water interface in the form of reunion. The Raman spectra detected the hydrolysis degree of ODSA and reflected the density of particulate film. The emulsion with different particles concentration showed obvious shear thinning behavior, and had a strong network structure and self-healing capability. When a magnetic field was applied to the fresh emulsion, the particles would be attracted toward the magnet and be pulled away the films, which would resulting in film rupture and final demulsification. And the emulsion could not be recovered when the magnet was removed.2. Pickering-type ODSA emulsion stabilized by nano-SiO2 particles grafted with DMAEMA. The surface properties and morphology of the modified nano-SiO2 microspheres was characterized. PDMAEMA is a kind of weak electrolyte, the deprotonation of dimethylamino could make particles be negative charged in alkaline condition. The repulsive force of particles would make for good stability, the effective diameter of particles on oil/water decreased which helped good stability. Adjusting the pH value of emulsion, the styability would decrease and easily recover. The critical particles concentration was 1.0 wt%, the module of G’was related to the 3D network in continuous phase. CLSM shows the adsorption behavior and dynamic variation of emulsion. Raman spectra showed the ODSA was almostly hydrolyzed after 24 h.3. Pickering-type AKD emulsion stabilized by modified cellulose nanocrystals (CNCs) with AKD in water. The physic-chemical properties and morphogy of CNCs before and after modification were characterized. The grafted CNCs had improved hydrophobicity and would decrease the surface tension of water dispersion to 54 mN/m. The Pickering-type AKD emulsion had good stability at 3.0 wt% of grafted CNCs without separated water and AKD after 12 h. The addation of NaCl would result in flocculation of grafted CNCs, the emulsion showed good stability when the concentration of NaCl was 0.002 wt%. According to the AKD emulsion model, it indicated that the grafted CNCs existed on the oil/water interface in the form of dense arrangement. With the increasing dosage of AKD, the sizing degree improved.4. Pickering emulsion liquid membrane consisted of Pickering emulsion stabilized by grafted Fe3O4 nanoparticles and effluent. The stability of Pickering emulsion was an important factor for extracting process, the emulsion achieved good stability when Cp=0.5 wt%, Row=2, CNaOH=0.5 mol 1-1. With stable Pickering emulsion, the dosage of carrier (TBP) had the most impact on extract efficiency, the addation of carrier would enhance the density gradient of mass transfer and raise the extraction for 4-Methoxylphenol. When ReW=1:5, CTBP=30%, the liquid membrane could achieve the extraction yield of 80% in 5 min. Stirring rate would decrease the oil film thickness and improve the dispersibility of Pickering emulsion, the system attained good extraction effect at 250 rpm. When phenolic compounds were mixed in the effluent, the molecular with high bonding strength with TBP had better extraction efficiency. Demulsified the emulsion after extracting process with magnet, recovered particles and oil, the purified particles and oil had good recycling property by testing the extracting efficiency.